Well they would just be there for the howler, they shouldn't be getting involved much at all. They would just be there in case of something blatant that was missed. Your complaint that they did "fuck all" when that was tried in the past isn't a bad thing. That was probably because there was no need for them to get involved because nothing major was missed. When that was tested, do you recall any howlers or any reason for them to get involved?
The end line assistants would also be better suited to communicate with the VAR crew upstairs rather than the main referee being distracted by the VARs. The primary issue with the VAR system in place is how they are able to influence the referee by having a direct line to the referee. Also the main referee shouldn't be running over to a monitor at mid pitch. VAR (systemically) would be better with end line assistants being the video reviewers on the pitch rather than the main referee. VAR would be much better if the VARs could only communicate with the end line assistants, then the end line assistants could review and decide whether they need to notify the main referee of a missed error.
I bring this up because, as much as much as I want VAR gone completely, as it stands, the system in place is so poorly designed that I want to at least try to show a way that it could possibly be improved. I have yet to hear any real suggestions to make VAR better. End line assistants could not only see incidents that the main referee misses, but they could also be the ones to communicate with the VARs upstairs, and perhaps review footage from an end line monitor, and then advise the main referee by stepping on to the pitch and getting his attention. I don't like the fact that the main referee has an earpiece. I would like to see the main referee not have an earpiece, and task the end line assistants who are stationed near each goal to be the ones to communicate with the VARs upstairs, and review the footage, so the main referee can fully focus on the match at hand, and wouldn't have to be distracted by the VARs in his ear.